Torque Shoulder of a Premium Connection

ABSTRACT

A threaded tubular connection is provided. The threaded tubular connection includes a pin having external threads, a pin seal surface, and a pin torque shoulder at a free end and a box for receiving the pin, the box having internal threads for interacting with the pin threads, a box seal surface for contacting the pin seal surface and a box torque shoulder for contacting the pin torque shoulder. The pin and box define a longitudinal axis. The pin torque shoulder has a first pin shoulder surface and a second pin shoulder surface, the first pin shoulder surface intersects an axis perpendicular to the longitudinal axis at a first angle and the second pin shoulder surface intersects the perpendicular axis at a second angle. The box torque shoulder has a first box shoulder surface and a second box shoulder surface. The first box shoulder surface intersects an axis perpendicular to the longitudinal axis at a third angle and the second box shoulder surface intersects the perpendicular axis at a fourth angle. A further tubular connection and method are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 15/449,350 filed onMar. 3, 2017, the entire disclosure of which is hereby incorporated byreference herein.

The present invention relates to threaded pipes and connectors for suchpipes which may be used in the oil and natural gas industry. Forexample, a pipe can have an end with a pin that fits into a box at oneend of a connector, the pipe and connector being connected by threading.The connector can have a second box for a second pipe with a second pin,so that the pipe and the second pipe are connected via the connector.

BACKGROUND

WO Publication No. 84/04352 purportedly describes a tubular joint orconnector of box and pin members having two-step tapered threads. Twometal to metal seals of complementary engaging sealing surfaces areprovided. Reverse angle torque shoulders at the end of the pin memberand the interior termination of the box member and hooked threadsfurther characterize the joint and box and pin members.

U.S. Pat. No. 4,623,173 purportedly describes a screw joint coupling foroil pipes. A main sealing portion is provided with a sealing portionwhich is axially convex at an end of a male screw, and with a sealingportion which is tapered at an inner side of a female screw, and an endpoint of the male screw butting an end part of a stopper formed at theinner side of the female screw.

U.S. Pat. No. 4,624,488 purportedly describes a tubular connection thathas cooperating internal frusto-conical sealing surfaces on acounterbore of the box member and a free end of the pin member. Theinternal sealing surface of the pin member inclines inwardlysubstantially at fourteen degrees from the axis of the tubularconnection adjacent the end of the pin member. The angle of the inclineof the box internal sealing surface is substantially the same as that ofthe pin internal surface. A pilot surface or bull nose disposed from adistal-proximate end to the distal end of the pin member inclining to alesser extent than the angle of the incline of the internal surface ofthe pin member being substantially parallel to the axis of theconnection; defines an increased end-of-pin flat thickness.

U.S. Pat. No. 7,334,821 purportedly describes a threaded tubularconnection with a male threaded element and a female threaded element.The male threaded element has male threading and a free end, with anon-threaded lip between the threading and the free end. The femalethreaded element has an internal tapered female threading and anon-threaded portion between the female threading and a lug. The femalethreaded element comprises an annular axial abutment surface. Aftercomplete makeup of the male threading in the female threading, the freeend bears against the annular axial abutment surface, which otherbearing surfaces radially interfere and are under metal-metal contactpressure to constitute metal-metal sealing surfaces.

In the '821 patent, another axial abutment surface thus is formed on afront surface of the free end of the male threaded element, and a singlelip sealing surface is disposed on the lip at an axial distance from theend of the threading. The lip comprises, between the distal axialabutment surface and the single lip sealing surface, an appendix havinga peripheral surface facing the female threaded member that is distinctfrom the lip sealing surface.

U.S. Publication No. 2014/0145433 purportedly describes a tubularconnection including a pin and box member. The pin member has a firstthread structure and a helical torque shoulder spaced axially along thepin member from the first thread structure. The box member has a secondthread structure and a second helical torque shoulder spaced axiallyalong the box member from the second thread structure. Upon rotation,the helical torque shoulders engage one another.

SUMMARY OF THE INVENTION

During make-up of a premium connection between a threaded tube with apin, such as a pipe, and a threaded tube with a box, such as aconnector, the following sequence occurs: (1) the pin on the pipe isstabbed into the connector until thread crests touch; (2) the pin isthen screwed into the box until the pin seal surface initially touchesthe box seal surface, to define a position referred to as “hand tight”;(3) the pin is further screwed into the box until an end of the pin, aso-called torque shoulder, just touches a corresponding torque shoulderon the box, to define a position referred to as “shoulder tight”, withthis additional turning from the hand tight to the shoulder tightpositions causing an interference fit between the pin and box seals; and(4) then the pin is further tightened to create an additional torque todefine a final made up position is referred to as “power tight”.

A distance between the pin torque shoulder and box torque shoulder whenthe connection is at the hand tight position is called “standoff” Thestandoff is eliminated once the shoulder tight position is reached. Alarge standoff may be problematic because the pin seal surface and boxseal surface are in contact while the standoff is being eliminated. If alarge amount of turning is needed to reduce a large standoff, galling ofthe seal surfaces occurs, thereby compromising the seals.

An object of the present invention is to provide torque shoulder thatsecures or traps the pin in the box thereby reducing or eliminatingmovement of the pin with respect to the box. For example, the torqueshoulders will prevent the pin from moving, bending or deforming in theradial direction.

An alternate or additional object is to provide a connection that iseasy to manufacture.

The present invention provides a threaded tubular connection. Thethreaded tubular connection includes a pin having external threads, apin seal surface, and a pin torque shoulder at a free end and a box forreceiving the pin, the box having internal threads for interacting withthe pin threads, a box seal surface for contacting the pin seal surfaceand a box torque shoulder for contacting the pin torque shoulder. Thepin and box define a longitudinal axis. The pin torque shoulder has afirst pin shoulder surface and a second pin shoulder surface, the firstpin shoulder surface intersects an axis perpendicular to thelongitudinal axis at a first angle and the second pin shoulder surfaceintersects the perpendicular axis at a second angle. The box torqueshoulder has a first box shoulder surface and a second box shouldersurface. The first box shoulder surface intersects an axis perpendicularto the longitudinal axis at a third angle and the second box shouldersurface intersects the perpendicular axis at a fourth angle.

The present invention further provides another threaded tubularconnection. The threaded tubular connection includes a pin, the pinhaving internal threads, a pin seal surface, and a pin torque shoulderat a free end and a box for receiving the pin, the box having externalthreads for interacting with the external threads, a box seal surfacefor contacting the pin seal surface and a box torque shoulder forcontacting the pin torque shoulder. The pin and box define alongitudinal axis. The pin torque shoulder has at least one pin shouldersurface having a pin radius, the at least one pin shoulder surface iscurved with respect to the longitudinal axis. The box torque shoulderhas at least one box shoulder surface having a box radius, the at leastone box shoulder surface is curved with respect to the longitudinalaxis.

The present invention also provides a method for forming a threadedtubular connection. The method includes the steps of:

providing a pin having external threads, a pin seal surface and a pintorque shoulder at a free end, the pin torque shoulder including a firstpin shoulder surface extending in a first direction and a second pinshoulder surface extending in a second direction,

providing a box having internal threads, a box seal surface and a boxtorque shoulder at a free end, the box torque shoulder including a firstbox shoulder surface extending in a third direction and a second boxshoulder surface extending in a fourth direction,

stabbing the pin into the box to engage the external threads andinternal threads with one another;

rotating the pin with respect to the box until the pin seal surfacecontacts the box seal surface; and

further rotating the pin with respect to the box until the first boxshoulder surface contacts the first pin shoulder surface and the secondbox shoulder surface contacts the second pin shoulder surface.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will be elucidated withreference to the following drawings, in which:

FIGS. 1A to 1D show details of a torque shoulder as known in the art;

FIGS. 2A and 2B show a cross section view of a premium connection for anoil pipe according to the present invention, in a second stage ofmake-up, the hand tight position;

FIGS. 3A and 3B show the connection in a third stage of make-up, theshoulder tight position;

FIG. 4 shows a cross section view of a premium connection for an oilpipe according to the present invention, a pin of the oil pipe beingstabbed into a box of the connector;

FIGS. 5A and 5B show details of the torque shoulder according to thepresent invention and as shown in FIGS. 2A to 4;

FIGS. 6 to 8 show details of additional embodiments of torque shouldersaccording to the present invention;

FIG. 9 shows a force diagram of the forces applied to a pin inaccordance with the embodiment shown in FIGS. 5A and 5B;

FIGS. 10A and 10B show a further preferred embodiment of a torqueshoulder according to the present invention; and

FIGS. 11A and 11B show another preferred embodiment of a torque shoulderaccording to the present invention.

DETAILED DESCRIPTION

FIG. 1A shows a traditional torque shoulder and metal-to-metal sealcombination as known in the art. Box 1520 includes box seal surface 1524and box torque shoulder 1526. Pin 1420 includes pin seal surface 1424,nose 1428 and pin torque shoulder 1426. As shown in FIG. 1, pin sealsurface 1424 is located at an end of pin 1420. The nose 1428 of pin 1420is wedged between pin seal surface 1424 and pin torque shoulder 1426when the connection is formed. The connection of pin 1420 and box 1520defines a longitudinal axis of the pipe and connector (not shown). Anaxis X is perpendicular to the longitudinal axis and runs through theend of the torque shoulders 1426, 1526 at pin nose 1428. Pin torqueshoulder 1426 and box torque shoulder 1526 each include a singleshoulder surface that is angled with respect to perpendicular axis X. Aninterior angle A formed between torque shoulders 1426, 1526 andperpendicular axis X may be, for example, approximately −15°, that is,15° in the clockwise direction from axis X. This angle of incline isknown in the prior art. In this example the pin nose 1428 is tightlywedged between box seal surface 1524 and box torque shoulder surface1526. See for example, U.S. Pat. No. 7,334,821.

FIG. 1D shows a premium connection as known in the prior art. FIG. 1Bshows a close up of the connection of FIG. 1D when the torque shoulders1426, 1526 just begin to contact. A gap Sc exists between an outersurface of pin 1420 and a counter-bore surface of box 1520 and isnecessary for ease of assembly. While angle A is beneficial to lock thepin 1420 and box 1520 together after assembly, FIG. 1C shows that,during further screwing of the connection, angle A causes the pin 1420to crash into the box 1520. This undesirable contact can prevent properpositioning of the connection during assembly and may cause damage toseal surfaces 1424, 1524 or torque shoulders 1426, 1526.

In accordance with the present invention, a premium connection isprovided that includes advantages over the prior art, for example,movement of the pin may be controlled and the undesirable contact anddamage to seal surfaces discussed above may be reduced. The premiumconnection includes pin and box torque shoulders with a plurality ofsurfaces, for example, each torque shoulder may have a top and bottomtorque shoulder surface with respect to the orientation shown in FIGS.2A to 11B. Another feature according to the present invention alsoincludes seal surfaces that are spaced apart from the shoulder surfacesas shown in FIGS. 2A, 3A and 10A. A further feature includes a spaceexisting between an edge of the pin and an edge of the box or connectoreven after the pin is in a final position. See FIGS. 5A and 6 to 8 and10A.

In a preferred embodiment, both torque shoulders, top and bottom, of thepin and box may contact each another at the same time. Thus, theconnector provides a neutral trap for the pin. In another preferredembodiment, top torque shoulder surfaces of the pin and box may contactone another prior to bottom torque shoulder surfaces of the pin and boxcontacting one another. In this embodiment, the pin may bend downward.See FIG. 6. In a further preferred embodiment, bottom torque shouldersurfaces of the pin and box may contact one another prior to the toptorque shoulder surfaces of the pin and box contacting one another. Inthis embodiment, the pin may bend upward. See FIGS. 2B and 3B. As aresult, the movement of the pin can be controlled as desired.

FIG. 4 shows a cross section view of an oil pipe 10 and a connector 100,in a first stage, the stabbed position. FIGS. 2A and 2B show theconnection with oil pipe 10 and connector 100, in a second stage, afterrotation has occurred. Oil pipe 10 has a pin 20 with a threaded section22, a pin seal surface 24 and a torque shoulder 26 at a free end. Pintorque shoulder 26 includes first surface 26 a and second surface 26 b.Connector 100 has two boxes 120, 120′. Each box 120, 120′ has a threadedsection 122, a box seal surface 124 and a torque shoulder 126 on aradially inwardly projection 150. Box torque shoulder 126 includes firstsurface 126 a and second surface 126 b. In this embodiment, the firstbox shoulder surface 126 a is complementary with the first pin shouldersurface 26 a and the second box shoulder surface 126 b is complementarywith the second pin shoulder surface 26 b.

Connector 100 has two free ends 102 and 102′ as shown in FIG. 4. Asdescribed above, in the stabbed position, oil pipe 10 is stabbed orplaced into connector 100 until threaded section 22 of pin 10 contactsthreaded section 122 of boxes 120, 120′. Rotation has not yet occurredbetween pin 10 and boxes 120, 120′. The rotation of pin 10 and boxes120, 120′ forms the connection.

This second stage of makeup is known as the hand tight position in whichthe threads 22, 122 or seal surfaces 24, 24 just begin to touch oneanother. Threads 22 of pin 20 engage threads 122 of box 120. Pin sealsurface 24 and box seal surface 124 just begin to touch. A gap orstandoff “Sa” exists between the first surfaces 26 a, 126 a of pintorque shoulder 26 and box torque shoulder 126 and a gap or standoff“Sb” exists between the second surfaces 26 b, 126 b of pin torqueshoulder 26 and box torque shoulder 126 in the hand tight position. Inthis embodiment, the standoff Sa is, for example, approximately 0.060in. and the standoff Sb is, for example, approximately 0.030 in. Thestandoffs Sa and Sb may vary as a result of the designed sealinterference and seal angles and do not have to be equal.

A nose 27 extends at an end of pin 20. Nose 27 is located between aninner surface 21 and an outer surface 23 of pin 20 and along a length oftorque shoulder 26 in a direction of axis P, an axis that isperpendicular to the longitudinal axis. The nose 27 is a vertexconnecting first surface 26 a and second surface 26 b of torque shoulder26. In this embodiment, first surface 26 a extends in one direction fromouter surface 23 to nose 27 and in a second direction around an outercircumference of pipe 10. Second surface 26 b extends in one directionfrom inner surface 21 to nose 27 and in a second direction around aninner circumference of pipe 10. The location of nose 27 is differentfrom the position of nose 1428 shown in FIG. 1A. In FIG. 1A, the nose islocated at one end of the torque shoulder 1426 at an outer surface ofthe pin 1420 and at or near the pin seal surface 1424. As shown in FIGS.2A to 11, nose 27 is not located at one end of the pin torque shoulder26. Instead nose 27 is in a middle or central part of pin torqueshoulder 26 with regard to a length of shoulder 26 in the profile view.The shape of nose 27 may vary and can be, for example, angular, socket,a flattened edge, a bull nose, bulb, cone, rounded, fishtail, etc. Adepression 127 is located along a length of torque shoulder 126 in adirection perpendicular to the longitudinal axis and is a vertexconnecting first surface 126 a and second surface 126 b. In thisembodiment, the geometry of nose 27 and depression 127 are complementaryso nose 27 and depression 127 fit together when pin 10 is screwed intoconnector 100; depression 127 contacts nose 27 and pin shoulder 26contacts box shoulder 126. (FIG. 5).

The difference in width between standoff Sa and standoff Sb occursbecause nose 27 is not initially aligned with depression 127 withrespect to the longitudinal axis. As shown in FIGS. 2B and 3B, nose 27is situated below depression 127. This offset between nose 27 anddepression 127 forces pin 10 to bend upwards as nose 27 is received indepression 127. Bending pin 10 forces nose 27 into depression 127 andresults in a tighter connection. In a different embodiment, nose 27 maybe situated above depression 127 so the pin is forced to bend downwardsthereby also resulting in a tighter connection. See, for example, FIG.6.

FIGS. 3A and 3B show the third stage of make-up, a first shoulder tightposition, which occurs after further rotation of pin 20 with respect tobox 120. The seal surfaces 24, 124 are forced together by screwing pin20 into box 120 until torque shoulders 26, 126 contact one another. Inthis preferred embodiment, for example, the complementary secondsurfaces 26 b, 126 b just contact one another. As a result, the standoffSb between second surfaces 26 b, 126 is eliminated. However, standoff Sabetween complementary first surfaces 26 a, 126 a still exists.Additional rotation has not yet occurred after the point of contactbetween shoulders 26, 126 so there is no additional torque force appliedto shoulders 26, 126, in this position. A distance 51 in the radialdirection exists between the edge of pin 20 and surface BS of box 120.The relative angles of seal surfaces 24, 124, force apart an edge of pin20 and surface BS of box 120 by an amount of seal interference 51designed into the connection to provide sufficient contact pressure inorder to form a leak tight seal.

The fourth stage of make-up, a second shoulder tight position, occursafter further rotation of pin 20 with respect to box 120. The sealsurfaces 24, 124 are further forced together by screwing pin 20 into box120 until torque shoulder first surfaces 26 a, 126 a contact oneanother. The radial distance 51 is reduced by the amount of the radialoffset between vertices 27, 127. Forcing the end of the pin radiallyoutward forces the seal surfaces 24,124 tighter together creating abetter seal. The V shape between the first and second shoulder surfaceskeeps gap 51 from being zero and causing undesirable contact between thebox and pin.

The fifth and final stage of making up the connection is the power tightposition. During the power tight stage additional torque is applied totorque shoulders 26, 126 but very little additional rotation occurs,about 0.01 turns, for example. Because very little additional rotationoccurs, the power tight position for the connection looks like theshoulder tight position shown in FIGS. 3A and 3B.

The amount of torque build up is a function of friction, stiffness ofthe pin, stiffness of the box around the seal area, the amount of threadinterference, if any, the lubricant and the amount of interference inthe seals. Once seal surfaces 24, 124 contact each other, torque beginsto build up rapidly. The torque build up is caused by seal surfaces 24,124 being wedged together. The torque continues increasing at anapproximately constant rate until the shoulders 26, 126 contact in theshoulder tight position. The torque builds up extremely rapidly aftershoulders 26, 126 contact one another. Once shoulders 26, 126 contact,additional torque is applied until the pre-determined power tightposition is reached and the desired amount of torque is achieved. Verylittle additional rotation of the connection is needed to reach thedesired final make-up torque, for example, approximately 0.01 turns.

FIGS. 5A and 5B shows a cross section view of a torque shoulderembodiment in accordance with the present invention. As shown in FIGS.5A and 5B, in the embodiment of FIGS. 2A to 4, pin 20 is designed as amale component and box 120 is designed as a female component so box 120can receive pin 20. In this embodiment, pin torque shoulder 26 and boxtorque shoulder 126 both have a V-shaped cross section. Pin seal surface24 and box seal surface 124 are spaced apart from each respective torqueshoulder 26, 126, with respect to a longitudinal axis (not shown)defined by the connection of the pipe and connector. Torque shouldersmay also have cross sections of another shape or design.

The V shaped extension of pin torque shoulder 26 engages with the Vshaped receptacle of box torque shoulder 126 to reduce or preventmovement of pin 20 in multiple directions, e.g., radially inward oroutward. For example, first surfaces 26 a, 126 a prevent pin 20 frombeing driven upwards into a corner of box 120 by keeping the nose 27 ofpin 20 down. And, second surfaces 26 b, 126 b prevent externally appliedpressure from forcing pin 20 inward which de-energizes seal surfaces 24,124.

An interior angle Va is formed between first surfaces 26 a, 126 a andaxis P. Interior angle Va may be 15°, which is 15° in thecounter-clockwise direction with respect to axis P. An interior angle Vbis formed between second surfaces 26 b, 126 b and axis P. Interior angleVb may be −15°, which is 15° in the clockwise direction with respect toaxis P. Angles Va, Vb may vary and be, for example, from 3 to 60°, −3 to−60°, respectively. In addition, interior angle Va may be different fromor equal to an absolute value of interior angle Vb. For example, asshown in FIG. 5B, angle Va is 15° and is not equal to an absolute valueof angle Vb which is −45° because 15°≠|−45°| so Va≠|Vb|. In anotherexample, angle Va may be 20° and angle Vb may be −10° in which caseVa≠|Vb| because 20°≠|−10°|.

As shown in FIG. 5B, nose 27 and depression 127 are located at or near acenter torque shoulders with respect to a length of shoulders 26 a, 26b, 126 a, 126 b in the direction of axis P. First pin surface 26 a hasthe same or near similar length to second pin surface 26 b and first boxsurface 126 a has the same or similar length to second box surface 126.In the FIG. 5B embodiment, nose 27 and depression 127 serve as thevertex of interior angles Va, Vb however, this is a non-limiting exampleof a preferred embodiment. The geometry of torque shoulders 26, 126including nose 27, depression 127 and angles Va, Vb is variable.Different shapes and positions of vertices may be used. Different shapesor angles of surfaces 26 a, 26 b, 126 a, 126 b or Va, Vb may be used.For example, the position of nose 27 does not have to be in a center oftorque shoulder 26 but instead could be located closer to inner surface21 than outer surface 23.

As shown in another preferred embodiment in FIG. 6, first surfaces 26 a,126 a are longer than second surfaces 26 b, 126 b and first angle Va isgreater than the absolute value of second angle Vb. FIG. 7 shows firstsurfaces 26 a, 126 a are shorter than second surfaces 26 b, 126 b andfirst angle Va is less than second angle Vb. The geometry of firstsurfaces 26 a, 126 a, second surfaces 26 b, 126 b and vertices (nose,depression) 27, 127 are designed to produce the desired results. Asdiscussed above, the vertices 27, 127 may be initially mis-aligned toforce an end of the pin down in order to straighten out or minimizebending of the pin, for example. Or, for example, the end of pin 20 mayneed to be forced up in order to increase contact pressure on the seals24, 124.

FIG. 8 shows another preferred embodiment of torque shoulders 26, 126 inwhich the shoulders 26, 126 have a bullet, bull nose or curved shapecross section as opposed to the V shaped cross section shown in FIGS. 5to 7. First surface 26 a has a first radius Ra, second surface 26 b hasa second radius Rb, first surface 126 a has a third radius Rc and secondsurface 126 b has a fourth radius Rd. First and third radii Ra, Rc, maybe different from or equal too second and fourth radii, respectively Rb,Rd. Nose 27 is located between first surface 26 a and second surface 26b. Depression 127 is located between first surface 126 a and secondsurface 126 b. As discussed above with respect to the V-shaped crosssection embodiment, first surfaces 26 a, 126 a, second surfaces 26 b,126 b and radii Ra, Rb, Rc, Rd and vertices may be adjusted to force pin20 up or down to trap pin 20 in a desired position with respect to thebox 120. In another embodiment the pin may having a single surface witha single radius and the box may have a single surface with a singleradius. In this embodiment, the pin radius and box radius may or may notbe equal and centerlines of the radii may or may not be the samedistance from the axis. If the two radii are offset radially withrespect from each other then the end of the pin will be either forcedupwards or downwards, depending upon how the two radii are offset.

The V shaped cross section and bull nose cross section designs of torqueshoulders 26, 126 is advantageous over the prior art because the maleand female geometry traps or constrains pin in a radial position withinthe box and thereby reducing or preventing movement of the pin. Byadjusting the design of shoulders 26, 126, bending, bowing or deflectionof the pin may be compensated for or minimized. In addition, the contactpressure of the seal surfaces 24, 124 maybe increased. Other benefitsmay be derived therefrom as well.

Preferably, first and second angles Va, Vb or first and second radii Ra,Rb are designed to be small enough so a larger component of force Facting on pin 20 is an axial component A and not a radial component R.See FIG. 9.

FIGS. 10A and 10B show a torque shoulder connection for a pin and box inwhich the V-shaped shoulder design is inverted compared to theembodiments shown in FIGS. 2A to 9. In this embodiment, pin 220 is afemale member and box 320 is a male member. Box 320 includes a box sealsurface 324, first shoulder surface 326 a, second shoulder surface 326b. A nose 327 is formed between first shoulder surface 326 a and secondshoulder surface 326 b. Pin 220 includes a pin seal surface 224, firstshoulder surface 226 a and a second shoulder surface 226 b. A depression227 is formed between first shoulder surface 226 b and second shouldersurface 226 b. In this embodiment, the vertex between box surfaces 326 aand 326 b forms nose 327 and the vertex between pin surfaces 226 a and226 b forms depression 227. Nose 327 and depression are complementarysurfaces so nose 327 is received in depression 227 by rotation of pin220 in box 320 in the same manner as discussed above with respect toFIGS. 2a to 5B. This inverted shoulder design may also apply to the bullnose embodiment shown in FIG. 8.

FIGS. 11A and 11B show a torque shoulder connection wherein the pin 520and box 420 have different shoulder surface geometries and vertices 527and 427 are not complementary with one another according to a furtherpreferred embodiment of the present invention. FIG. 11A shows a pin 520having a rounded or bull nosed shoulder surface 526 with a firstshoulder surface 526 a and a second shoulder surface 526 b. A vertex 527is located between the first shoulder surface 526 a and second shouldersurface 526 b. Box 420 includes a v-shaped box shoulder surface 426 witha first shoulder surface 426 a and second shoulder surface 426 b. Avertex 427 is located between the first shoulder surface 426 a andsecond shoulder surface 426 b. Pin 520 and box 420 contact one anotherin the same manner as described above with respect to FIGS. 2A to 5B.Rotation of pin 520 into box 420 provides for contact of first shouldersurface 526 a with first shoulder surface 426 a and for contact ofsecond shoulder surface 526 b with second shoulder surface 426 b. In theembodiments shown in FIGS. 11A and 11B, vertex 427 and vertex 527 maynot be in contact with one another due to the different surfacegeometries of shoulder 526 and shoulder 426. A gap or space 530 will bepresent between vertices 426, 526 after makeup. Also, due to thevariation in geometry and design of shoulder surfaces 526, 426, shouldersurfaces 526, 426 will not be in contact with one another along aportion of surfaces 526, 426.

FIG. 11B shows a pin 520 having a v-shaped pin shoulder surface 526 anda box 420 with a rounded or bull nosed box shoulder surface 426. Pinshoulder surface 526 has a first shoulder 526 a and a second shouldersurface 526 b. A vertex 527 is located between the first shouldersurface 526 a and second shoulder surface 526 b. Box shoulder surface426 has a first shoulder surface 426 a and second shoulder surface 426b. A vertex 427 is located between the first shoulder surface 426 a andsecond shoulder surface 426 b. Pin 520 and box 420 contact one anotherin the same manner as described above with respect to FIGS. 2A to 5B and11A. Rotation of pin 520 into box 420 provides for contact of firstshoulder surface 526 a with first shoulder surface 426 a and for contactof second shoulder surface 526 b with second shoulder surface 426 b. Aspace 530 is present between vertices 427 and 527.

In FIGS. 11A and 11B, the pin 520 and box 420 may be designed so thatvertices 527 and 427 are aligned with each other so pin shouldersurfaces 526 a, 526 b contact box shoulder surfaces 426 a, 426 b at thesame time when pin 520 is being inserted into box 420 during make-up.Alternatively, the shoulder surfaces 526, 426 and vertices 527, 427 maybe designed so first shoulder surfaces 526 a, 426 a contact first, thensecond shoulder surfaces 526 b, 426 b contact as pin 520 is furtherscrewed into box 520. In another variation, the shoulder surfaces 526,426 and vertices 527, 427 may be designed so second shoulder surfaces526 b, 426 b contact first, then first shoulder surfaces 526 a, 426 acontact as pin 520 is further screwed into box 520.

Shoulder surfaces 426, 526 may be designed with a variety of geometries,including, but not limited to, bull nose, bullet shaped, angular,rounded or fishtail, for example.

In the preceding specification, the invention has been described withreference to specific exemplary embodiments and examples thereof. Itwill, however, be evident that various modifications and changes may bemade thereto without departing from the broader spirit and scope ofinvention as set forth in the claims that follow. The specification anddrawings are accordingly to be regarded in an illustrative manner ratherthan a restrictive sense.

1. A threaded tubular connection comprising: a pin, the pin havingexternal threads, a pin seal surface, and a pin torque shoulder at afree end; and a box for receiving the pin, the box having internalthreads for interacting with the external threads, a box seal surfacefor contacting the pin seal surface and a box torque shoulder forcontacting the pin torque shoulder; the pin and box defining alongitudinal axis, the pin torque shoulder having a first pin shouldersurface and a second pin shoulder surface, the first pin shouldersurface intersecting an axis perpendicular to the longitudinal axis at afirst angle, the second pin shoulder surface intersecting theperpendicular axis at a second angle, the first pin shoulder surfaceforming a V-shape with the second pin shoulder surface the first pinshould surface and the second pin shoulder surface meeting at a pinvertex to define a nose, and the box torque shoulder having a first boxshoulder surface and a second box shoulder surface, the first boxshoulder surface intersecting an axis perpendicular to the longitudinalaxis at a third angle, the second box shoulder surface intersecting theperpendicular axis at a fourth angle, the first box shoulder surface andthe second box should surface forming a V-shaped receptacle and meetingat a box vertex to define a depression.
 2. The threaded tubularconnection as recited in claim 1, wherein the first, second, third andfourth angles have an absolute value from 3 to 60° with respect to theperpendicular axis.
 3. The threaded tubular connection as recited inclaim 2, wherein an absolute value of the first angle is different froman absolute value of the second angle.
 4. The threaded tubularconnection as recited in claim 1, wherein the first and third angles arepositive angles with respect to the perpendicular axis and the secondand fourth angles are negative angles with respect to the perpendicularaxis.
 5. The threaded tubular connection as recited in claim 1, whereinthe first pin shoulder surface is a different length than the second pinshoulder surface.
 6. The threaded tubular connection as recited in claim1, wherein the first pin shoulder surface is a same length as the secondpin shoulder surface.
 7. The threaded tubular connection as recited inclaim 1, wherein, the pin vertex and box vertex are offset from oneanother with respect to the longitudinal axis.
 8. The threaded tubularconnection as recited in claim 7, wherein an amount of the offset isselected to improve contact pressure between the pin sealing surface andbox sealing surface.
 9. The threaded tubular connection as recited inclaim 1, wherein the first and second angles are selected so a largercomponent of a force acting on the pin is an axial component force. 10.The threaded tubular connection as recited in claim 1, wherein the firstangle is equal to the third angle and the second angle is equal to thefourth angle. 11.-13. (canceled)
 14. The threaded tubular connection asrecited in claim 1, wherein the pin torque shoulder has a geometry thatis similar to a geometry of the box torque shoulder. 15-24. (canceled)25. A method for forming a threaded tubular connection comprising thesteps of: providing a pin having external threads, a pin seal surfaceand a pin torque shoulder at a free end, the pin torque shoulderincluding a first pin shoulder surface extending in a first directionand a second pin shoulder surface extending in a second direction andmeeting at a pin vertex to define a V-shape, providing a box havinginternal threads, a box seal surface and a box torque shoulder at a freeend, the box torque shoulder including a first box shoulder surfaceextending in a third direction and a second box shoulder surfaceextending in a fourth direction and meeting at a box vertex to define aV-shaped depression, stabbing the pin into the box to engage theexternal threads and internal threads with one another; rotating the pinwith respect to the box until the pin seal surface contacts the box sealsurface; and further rotating the pin with respect to the box until thefirst box shoulder surface contacts the first pin shoulder surface andthe second box shoulder surface contacts the second pin shouldersurface.
 26. The method for forming a threaded tubular connection asrecited in claim 25, wherein the first and third directions are the sameand the second and fourth directions are the same. 27-28. (canceled) 29.A threaded tubular connection comprising: a pin, the pin having externalthreads, a concave pin seal surface, and a pin torque shoulder at a freeend; and a box for receiving the pin, the box having internal threadsfor interacting with the external threads, a convex box seal surface forcontacting the concave pin seal surface and a box torque shoulder forcontacting the pin torque shoulder; the pin and box defining alongitudinal axis, the pin torque shoulder having a first pin shouldersurface and a second pin shoulder surface, the first pin shouldersurface intersecting an axis perpendicular to the longitudinal axis at afirst angle, the second pin shoulder surface intersecting theperpendicular axis at a second angle, and the box torque shoulder havinga first box shoulder surface and a second box shoulder surface, thefirst box shoulder surface intersecting an axis perpendicular to thelongitudinal axis at a third angle, the second box shoulder surfaceintersecting the perpendicular axis at a fourth angle